import {getOrder} from "../util/bidi.js"
import {ie, ie_version, webkit} from "../util/browser.js"
import {elt, eltP, joinClasses} from "../util/dom.js"
import {eventMixin, signal} from "../util/event.js"
import {hasBadBidiRects, zeroWidthElement} from "../util/feature_detection.js"
import {lst, spaceStr} from "../util/misc.js"

import {getLineStyles} from "./highlight.js"
import {
    attachMarkedSpans,
    compareCollapsedMarkers,
    detachMarkedSpans,
    lineIsHidden,
    visualLineContinued
} from "./spans.js"
import {getLine, lineNo, updateLineHeight} from "./utils_line.js"

// LINE DATA STRUCTURE

// Line objects. These hold state related to a line, including
// highlighting info (the styles array).
export class Line {
    constructor(text, markedSpans, estimateHeight) {
        this.text = text
        attachMarkedSpans(this, markedSpans)
        this.height = estimateHeight ? estimateHeight(this) : 1
    }

    lineNo() {
        return lineNo(this)
    }
}

eventMixin(Line)

// Change the content (text, markers) of a line. Automatically
// invalidates cached information and tries to re-estimate the
// line's height.
export function updateLine(line, text, markedSpans, estimateHeight) {
    line.text = text
    if (line.stateAfter) line.stateAfter = null
    if (line.styles) line.styles = null
    if (line.order != null) line.order = null
    detachMarkedSpans(line)
    attachMarkedSpans(line, markedSpans)
    let estHeight = estimateHeight ? estimateHeight(line) : 1
    if (estHeight != line.height) updateLineHeight(line, estHeight)
}

// Detach a line from the document tree and its markers.
export function cleanUpLine(line) {
    line.parent = null
    detachMarkedSpans(line)
}

// Convert a style as returned by a mode (either null, or a string
// containing one or more styles) to a CSS style. This is cached,
// and also looks for line-wide styles.
let styleToClassCache = {}, styleToClassCacheWithMode = {}

function interpretTokenStyle(style, options) {
    if (!style || /^\s*$/.test(style)) return null
    let cache = options.addModeClass ? styleToClassCacheWithMode : styleToClassCache
    return cache[style] ||
        (cache[style] = style.replace(/\S+/g, "cm-$&"))
}

// Render the DOM representation of the text of a line. Also builds
// up a 'line map', which points at the DOM nodes that represent
// specific stretches of text, and is used by the measuring code.
// The returned object contains the DOM node, this map, and
// information about line-wide styles that were set by the mode.
export function buildLineContent(cm, lineView) {
    // The padding-right forces the element to have a 'border', which
    // is needed on Webkit to be able to get line-level bounding
    // rectangles for it (in measureChar).
    let content = eltP("span", null, null, webkit ? "padding-right: .1px" : null)
    let builder = {
        pre: eltP("pre", [content], "CodeMirror-line"), content: content,
        col: 0, pos: 0, cm: cm,
        trailingSpace: false,
        splitSpaces: cm.getOption("lineWrapping")
    }
    lineView.measure = {}

    // Iterate over the logical lines that make up this visual line.
    for (let i = 0; i <= (lineView.rest ? lineView.rest.length : 0); i++) {
        let line = i ? lineView.rest[i - 1] : lineView.line, order
        builder.pos = 0
        builder.addToken = buildToken
        // Optionally wire in some hacks into the token-rendering
        // algorithm, to deal with browser quirks.
        if (hasBadBidiRects(cm.display.measure) && (order = getOrder(line, cm.doc.direction)))
            builder.addToken = buildTokenBadBidi(builder.addToken, order)
        builder.map = []
        let allowFrontierUpdate = lineView != cm.display.externalMeasured && lineNo(line)
        insertLineContent(line, builder, getLineStyles(cm, line, allowFrontierUpdate))
        if (line.styleClasses) {
            if (line.styleClasses.bgClass)
                builder.bgClass = joinClasses(line.styleClasses.bgClass, builder.bgClass || "")
            if (line.styleClasses.textClass)
                builder.textClass = joinClasses(line.styleClasses.textClass, builder.textClass || "")
        }

        // Ensure at least a single node is present, for measuring.
        if (builder.map.length == 0)
            builder.map.push(0, 0, builder.content.appendChild(zeroWidthElement(cm.display.measure)))

        // Store the map and a cache object for the current logical line
        if (i == 0) {
            lineView.measure.map = builder.map
            lineView.measure.cache = {}
        } else {
            ;(lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map)
            ;(lineView.measure.caches || (lineView.measure.caches = [])).push({})
        }
    }

    // See issue #2901
    if (webkit) {
        let last = builder.content.lastChild
        if (/\bcm-tab\b/.test(last.className) || (last.querySelector && last.querySelector(".cm-tab")))
            builder.content.className = "cm-tab-wrap-hack"
    }

    signal(cm, "renderLine", cm, lineView.line, builder.pre)
    if (builder.pre.className)
        builder.textClass = joinClasses(builder.pre.className, builder.textClass || "")

    return builder
}

export function defaultSpecialCharPlaceholder(ch) {
    let token = elt("span", "\u2022", "cm-invalidchar")
    token.title = "\\u" + ch.charCodeAt(0).toString(16)
    token.setAttribute("aria-label", token.title)
    return token
}

// Build up the DOM representation for a single token, and add it to
// the line map. Takes care to render special characters separately.
function buildToken(builder, text, style, startStyle, endStyle, css, attributes) {
    if (!text) return
    let displayText = builder.splitSpaces ? splitSpaces(text, builder.trailingSpace) : text
    let special = builder.cm.state.specialChars, mustWrap = false
    let content
    if (!special.test(text)) {
        builder.col += text.length
        content = document.createTextNode(displayText)
        builder.map.push(builder.pos, builder.pos + text.length, content)
        if (ie && ie_version < 9) mustWrap = true
        builder.pos += text.length
    } else {
        content = document.createDocumentFragment()
        let pos = 0
        while (true) {
            special.lastIndex = pos
            let m = special.exec(text)
            let skipped = m ? m.index - pos : text.length - pos
            if (skipped) {
                let txt = document.createTextNode(displayText.slice(pos, pos + skipped))
                if (ie && ie_version < 9) content.appendChild(elt("span", [txt]))
                else content.appendChild(txt)
                builder.map.push(builder.pos, builder.pos + skipped, txt)
                builder.col += skipped
                builder.pos += skipped
            }
            if (!m) break
            pos += skipped + 1
            let txt
            if (m[0] == "\t") {
                let tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize
                txt = content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"))
                txt.setAttribute("role", "presentation")
                txt.setAttribute("cm-text", "\t")
                builder.col += tabWidth
            } else if (m[0] == "\r" || m[0] == "\n") {
                txt = content.appendChild(elt("span", m[0] == "\r" ? "\u240d" : "\u2424", "cm-invalidchar"))
                txt.setAttribute("cm-text", m[0])
                builder.col += 1
            } else {
                txt = builder.cm.options.specialCharPlaceholder(m[0])
                txt.setAttribute("cm-text", m[0])
                if (ie && ie_version < 9) content.appendChild(elt("span", [txt]))
                else content.appendChild(txt)
                builder.col += 1
            }
            builder.map.push(builder.pos, builder.pos + 1, txt)
            builder.pos++
        }
    }
    builder.trailingSpace = displayText.charCodeAt(text.length - 1) == 32
    if (style || startStyle || endStyle || mustWrap || css) {
        let fullStyle = style || ""
        if (startStyle) fullStyle += startStyle
        if (endStyle) fullStyle += endStyle
        let token = elt("span", [content], fullStyle, css)
        if (attributes) {
            for (let attr in attributes) if (attributes.hasOwnProperty(attr) && attr != "style" && attr != "class")
                token.setAttribute(attr, attributes[attr])
        }
        return builder.content.appendChild(token)
    }
    builder.content.appendChild(content)
}

// Change some spaces to NBSP to prevent the browser from collapsing
// trailing spaces at the end of a line when rendering text (issue #1362).
function splitSpaces(text, trailingBefore) {
    if (text.length > 1 && !/  /.test(text)) return text
    let spaceBefore = trailingBefore, result = ""
    for (let i = 0; i < text.length; i++) {
        let ch = text.charAt(i)
        if (ch == " " && spaceBefore && (i == text.length - 1 || text.charCodeAt(i + 1) == 32))
            ch = "\u00a0"
        result += ch
        spaceBefore = ch == " "
    }
    return result
}

// Work around nonsense dimensions being reported for stretches of
// right-to-left text.
function buildTokenBadBidi(inner, order) {
    return (builder, text, style, startStyle, endStyle, css, attributes) => {
        style = style ? style + " cm-force-border" : "cm-force-border"
        let start = builder.pos, end = start + text.length
        for (; ;) {
            // Find the part that overlaps with the start of this text
            let part
            for (let i = 0; i < order.length; i++) {
                part = order[i]
                if (part.to > start && part.from <= start) break
            }
            if (part.to >= end) return inner(builder, text, style, startStyle, endStyle, css, attributes)
            inner(builder, text.slice(0, part.to - start), style, startStyle, null, css, attributes)
            startStyle = null
            text = text.slice(part.to - start)
            start = part.to
        }
    }
}

function buildCollapsedSpan(builder, size, marker, ignoreWidget) {
    let widget = !ignoreWidget && marker.widgetNode
    if (widget) builder.map.push(builder.pos, builder.pos + size, widget)
    if (!ignoreWidget && builder.cm.display.input.needsContentAttribute) {
        if (!widget)
            widget = builder.content.appendChild(document.createElement("span"))
        widget.setAttribute("cm-marker", marker.id)
    }
    if (widget) {
        builder.cm.display.input.setUneditable(widget)
        builder.content.appendChild(widget)
    }
    builder.pos += size
    builder.trailingSpace = false
}

// Outputs a number of spans to make up a line, taking highlighting
// and marked text into account.
function insertLineContent(line, builder, styles) {
    let spans = line.markedSpans, allText = line.text, at = 0
    if (!spans) {
        for (let i = 1; i < styles.length; i += 2)
            builder.addToken(builder, allText.slice(at, at = styles[i]), interpretTokenStyle(styles[i + 1], builder.cm.options))
        return
    }

    let len = allText.length, pos = 0, i = 1, text = "", style, css
    let nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, collapsed, attributes
    for (; ;) {
        if (nextChange == pos) { // Update current marker set
            spanStyle = spanEndStyle = spanStartStyle = css = ""
            attributes = null
            collapsed = null;
            nextChange = Infinity
            let foundBookmarks = [], endStyles
            for (let j = 0; j < spans.length; ++j) {
                let sp = spans[j], m = sp.marker
                if (m.type == "bookmark" && sp.from == pos && m.widgetNode) {
                    foundBookmarks.push(m)
                } else if (sp.from <= pos && (sp.to == null || sp.to > pos || m.collapsed && sp.to == pos && sp.from == pos)) {
                    if (sp.to != null && sp.to != pos && nextChange > sp.to) {
                        nextChange = sp.to
                        spanEndStyle = ""
                    }
                    if (m.className) spanStyle += " " + m.className
                    if (m.css) css = (css ? css + ";" : "") + m.css
                    if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle
                    if (m.endStyle && sp.to == nextChange) (endStyles || (endStyles = [])).push(m.endStyle, sp.to)
                    // support for the old title property
                    // https://github.com/codemirror/CodeMirror/pull/5673
                    if (m.title) (attributes || (attributes = {})).title = m.title
                    if (m.attributes) {
                        for (let attr in m.attributes)
                            (attributes || (attributes = {}))[attr] = m.attributes[attr]
                    }
                    if (m.collapsed && (!collapsed || compareCollapsedMarkers(collapsed.marker, m) < 0))
                        collapsed = sp
                } else if (sp.from > pos && nextChange > sp.from) {
                    nextChange = sp.from
                }
            }
            if (endStyles) for (let j = 0; j < endStyles.length; j += 2)
                if (endStyles[j + 1] == nextChange) spanEndStyle += " " + endStyles[j]

            if (!collapsed || collapsed.from == pos) for (let j = 0; j < foundBookmarks.length; ++j)
                buildCollapsedSpan(builder, 0, foundBookmarks[j])
            if (collapsed && (collapsed.from || 0) == pos) {
                buildCollapsedSpan(builder, (collapsed.to == null ? len + 1 : collapsed.to) - pos,
                    collapsed.marker, collapsed.from == null)
                if (collapsed.to == null) return
                if (collapsed.to == pos) collapsed = false
            }
        }
        if (pos >= len) break

        let upto = Math.min(len, nextChange)
        while (true) {
            if (text) {
                let end = pos + text.length
                if (!collapsed) {
                    let tokenText = end > upto ? text.slice(0, upto - pos) : text
                    builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
                        spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "", css, attributes)
                }
                if (end >= upto) {
                    text = text.slice(upto - pos);
                    pos = upto;
                    break
                }
                pos = end
                spanStartStyle = ""
            }
            text = allText.slice(at, at = styles[i++])
            style = interpretTokenStyle(styles[i++], builder.cm.options)
        }
    }
}


// These objects are used to represent the visible (currently drawn)
// part of the document. A LineView may correspond to multiple
// logical lines, if those are connected by collapsed ranges.
export function LineView(doc, line, lineN) {
    // The starting line
    this.line = line
    // Continuing lines, if any
    this.rest = visualLineContinued(line)
    // Number of logical lines in this visual line
    this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1
    this.node = this.text = null
    this.hidden = lineIsHidden(doc, line)
}

// Create a range of LineView objects for the given lines.
export function buildViewArray(cm, from, to) {
    let array = [], nextPos
    for (let pos = from; pos < to; pos = nextPos) {
        let view = new LineView(cm.doc, getLine(cm.doc, pos), pos)
        nextPos = pos + view.size
        array.push(view)
    }
    return array
}
